Showing papers by "Ram Nageena Singh published in 2019"

Seasonal variations in culturable archaea and their plant growth promoting attributes to predict their role in establishment of vegetation in Rann of Kutch

Abstract: Archaea are unique microorganisms that are present in ecological niches of high temperature, pH and high salinity. Archaea may be present freely or associated with plant rhizosphere. The plant-microbe interactions may be implicit to plants adaptation to abiotic stress of hypersalinity. With an aim to look for population dynamics of archaea at different seasons of the year in hypersaline environments of Rann of Kutch, the rhizospheric, non-rhizospheric, water and sediment samples were collected during autumn, winter and summer. Sampling sites were selected on the basis of topography and vegetation which included barren land, salt pan and rhizosphere of monocot and dicot plants. Soil pH and salinity (mS cm−1) varied from 7.4–10.15 and 1.19–106.7 respectively. A total of 157 halophilic archaea were isolated using seven different selective media. The isolated archaeal were screened for abiotic stress and it has been found they show the wide range of in the tolerance to temperatures (25–65 °C), NaCl concentrations (0.86–5.48 M), water stresses (upto −0.75Mpa) and pH (4–10). The profiling of archaeal community using 16S rRNA gene sequencing and phylogenetic analysis revealed that all archaeal isolates belonged to a family halobacteriaceae of phylum euryarchaeota. Based on 16S rRNA gene sequencing the cultures were identified and belonged to twenty eight distinct species of 16 genera namely Haladaptatus, Haloarcula, Halobacterium, Halococcus, Haloferax, Halogeometricum, Halolamina, Halopenitus, Halorubrum, Halosarcina, Halostagnicola, Haloterrigena, Natrialba, Natrinema, Natronoarchaeum and Natronomonas. In the present study, seasonal and niche-specific archaea were reported and characterized from hypersaline environments. The haloarchaea with multifunctional plant growth promoting attributes, prevalent in the hypersaline environments must be colonizing the rhizosphere of plants and contributing to the growth and sustenance of plants.

The impact of distillery effluent irrigation on plant-growth-promoting traits and taxonomic composition of bacterial communities in agricultural soil

Abstract: Long-term irrigation of agricultural fields with distillery effluent (DE) may alter the physical, chemical and biological properties of the soil. Microorganisms are critical to the maintenance of soil health and productivity. However, the impact of DE irrigation on activity and taxonomy of soil microorganisms is poorly understood. Here we studied plant-growth-promoting (PGP) traits and taxonomic composition of bacterial communities in agricultural soil irrigated with DE in conjugation with irrigation water, using cultivation-dependent and - independent methods. Most of the bacterial isolates obtained from DE irrigated soil were found to display PGP traits (phosphate solubilization, siderophore, indolic compounds and ammonia production). Diverse bacterial taxa were found in both culturable bacterial community and 16S rRNA gene clone library, which belonged to bacterial phyla Proteobacteria (Alpha-, Beta- and Gamma- subdivisions), Firmicutes, Actinobacteria, Acidobacteria, Bacteroidetes and Gemmatimonadates. Overall, these results indicate that PGP traits and taxonomic diversity of soil bacterial communities were not severely impacted by DE irrigation.